1. Field of the Invention
The invention relates to a cone/friction ring transmission, consisting of at least two subsidiary transmissions structured as cone/friction ring transmissions, and to a method for a cone/friction ring transmission having at least two subsidiary transmissions structured as cone/friction ring transmissions.
2. The Prior Art
Such a transmission is known from U.S. Pat. No. 1,709,346, whereby in these arrangements, a central cone is driven, which interacts with one or more output cones, by way of a friction ring, in each instance; these output cones are directed opposite the input cones, axis-parallel to them, disposed at a distance from the input cone that is constant over the cone mantle. The friction rings can be displaced along the gap, in each instance, by way of a common frame, so that a translation ratio between the input cone and the output cone can be adjusted in infinitely variable manner. The power take-offs of the power take-off cones, in each instance, are connected with the planets of a planetary gear, so that a torque applied by the input cone is divided up among the power take-off cones, in each instance, and totaled up again by way of the planetary gear, where a constant speed of rotation of the planets as well as of the power take-off cones is forced to occur as the result of coupling of the planets. However, this arrangement contains the problem that even tiny production tolerances or inaccuracies lead to friction losses between the friction rings and the cones.
Another embodiment of a transmission that can be adjusted in infinitely variable manner is known from JP 2000-291759, in which the friction rings are not guided along a gap by way of a common frame. Instead, each friction ring of each subsidiary transmission has an adjustment device that is mechanically independent of the others, which can be controlled by a common regulation device.
An alternative, known from WO 2004/063598 A1, proposes merging the power take-off cones, in each instance, of two parallel subsidiary transmissions that can be adjusted in infinitely variable manner, by means of a superimposition transmission on the power take-off. The need for equalizing the slip between an input cone and an output cone that occurs as the result of production tolerances or inaccuracies is eliminated, by way of the power-split joining of the power take-off shafts, because a total drive joined in this form allows differences in the speed of rotation between the subsidiary transmissions, in each instance. However, it is a disadvantage of such an embodiment that the increased complexity of the overall transmission and the increased number of friction pairings in the subsequent superimposition transmissions increase not only the production, assembly, and maintenance costs, but also the failure likelihood and the loss in degree of effectiveness.